Process for production of ketones



- cohols.

Patented Jaime 30, 1942 UNITED STATES PATENT orries PROCESS I OB PRODUCTION OFKETONES Benjamin '1. Brooks, on Greenwich, Conn., assignor to Standard Alcohol Company No Drawing. Application my 27, 1940,

Serial No. 34am 1o (Cl. 260-597) The present invention relates to the conversion of-olefln hydrocarbons. to ketches and more particularly, to the conversion of bothnormal" and branched chain oleflns of live or more car'- bon atoms to ketones'.

Lower molecular'weight ketones, such as ace- ,tone and methyl ethyl ketone, have heretofore been made satisfactorily in a number of ways among which is included both the oxidation and beginning the chemical operations of the present process. 1 r g The presence of saturated hydrocarbons in the raw material does not interfere with the chem:- ical operations of this process and they maybe subsequently separated as will be hereinafter more fully described.

According to the process of the present invention, an oleflnic hydrocarbon or a hydrocarbon mixture containing one or more olefins is treated with cold dilute aqueous hypochlorous action of sulfuric acid and not into alcohols.

Even when the branched chain olefins are iconverted in small yields to tertiary alcohols, the

latter cannot be oxidized or dehyd iienated to ketones.

The principal object of the present invention is to convert oleflns which are readily polymerized by sulfuric acid into ketones, Another obloci; of this inventio'n'is to treat hydrocarbon mixtures containing both normal and branched chain oleiins of live or more carbon atoms to produce ketones of .the branched chain hydrocarbons and at the same time to convert the normal chain oleflns into either ketones or other useful products such as glycols,

The olefin raw materials employed in manufacturing ketones, accordingto' the present invention, are oleflns of five or more carbon atoms from any convenient or economically feasible source, as, for example, oleiins made by the decomposition of chlorinated hydrocarbons; th

' .decompontion of alcohols, the catalytic dehydroof olellns and are particularly-advantageous as raw material for the'p'ractice of the presentinvention'and may be, if desired, flrstdistilled into fractions of narrow boiling point range before 65 normal glycols containing only primary and secacid solution, preferably according to the "process described in copending application Serial No. 306,805 filed November 30, 1939 to form. chlorohydrins. The chlorohydrin or mixture of chlorohydrins thus formed is treated with solid or concentrated caustic alkali, hydrated lime or miliroflime to yield epoxides. The conversion of chlorohydrins' to epoxides is preferably carried out at a temperature which will cause the epoxides to distill out as'rapidly as formed.

The olefin epoxide or mixture of hydrocarbons containing epoxide is then treated with cold dilute aqueous mineral acid, maintaining the temperature preferably below C. Sulfuric acid of from 0.1 to 1.0% concentration is the preferred acid although other mineral acids, such as nitric, may be used, and 0.5% is the preferred concentration; The dilute mineral acid causes the'epoxide to be hydrated to glycol. The lower' molecular weight glycols are freely water-soluble and inert hydrocarbons which may have been present in the original hydrocarbon mixture are preferably removed as an upper insoluble layer by decantation at this stage of the process. The solubility of the higher molecular weight glycols in water decreases with increasing molecular weight and in the case of hydrocarbon mixtures containing 8 or more carbon atoms to the-molecule, the inert saturated hydrocarbons, if present, are more advantageously removed from the glycols by distillation with steam.-

Glycols of five or more carbon atoms derived from branched chain oleflns and containing a tertiary hydroxyl group are rapidly converted to ketones by heating with aqueous dilute mineral acids such as sulfuric or phosphoric acids of about 5 to 15% concentration by weight, but underthese conditions the normal glycols remain substantially unchanged. O'Ihe temperature should be maintained at or slightly above the boiling point of the ketone produced. When the original hydrocarbon mixture yields both o ndary hydroxyl groups and branched chain glycols containing tertiary hydroxyl groups, slow distillation from dilute acid solutions of 5 to 15% concentration yields first the ketones derived from the branched chain olefins in a substantially pure state, and on continued distillation with increasing acid concentration causes more and more of the ketones of normal olefins to be formed. This is continued until the concentration of the acid reaches about 40%. Concentrations of sulfuric or phosphoric acid greater than Z=% cause coking or tar formation when making ketones of normal olefins and therefore the acid concentrationis preferably maintained at about 35% by replacing the water lost through distillation. Ketones up to about 12 carbon atoms distill readily with steam under these conditions, the boiling temperature of 35% sulfuric acid being about 108-110" C. While dilute mineral acids such as nitric o'r hydrochloric acid cause the catalytic hydration of oxides to glycols,

they are not suitable at the necessary concentrations for the conversion of glycols to ketones because of the formation of undesirable chlorination or nitration products.

The principles of the present invention are illustrated by the following examples:

Example 1 Trimethyl ethylene,

C=GHCHa CH3 was converted to the chlorohydrins by treating a cold dilute aqueous solution of calcium hypochlorite with carbon dioxide, agitating the aqueous solution of hypochlorous acid thus formed with the pentene. The chlorohydrin was converted to the epoxide, boiling point 73 I4= C., by passing it into a vessel filled with solid caustic soda, distilling the epoxide substantially as fast as formed. 300 parts of the epoxide were added slowly with agitation and cooled to 1500 parts of water containing 15 parts of sulfuric acid, maintaining the temperature below about 45 C. 50 parts f sulfuric acid were then added and the reaction mixture was slowly distilled, the ketone distilling readily with steam. The ketone was condensed and separated from the water yielding 182 parts of methyl isopropyl ketone boiling at 92.5-93 C. and 50 parts of a higher boiling ketone, boiling mainly at 162 C. The latter ketone is a condensation product of methyl isopropyl ketone and constitutes a valuable byproduct of the reaction.

Example 2 Example 3 500 parts of cracked refinery C5 out was treated with a cold dilute aqueous solution of calcium hypochlorite in the presence of carbon dioxide. The resulting mixture was then passed into a vessel containing solid caustic soda and maintained at a temperature and pressure sufiicient to' volatilize the unreacted hydrocarbons and the epoxides as rapidly as the epoxides are formed. The mixture of hydrocarbon and epoxides were then treated with a cold 1% solution of sulfuric acid which was constantly stirred and maintained at a temperature below 45 C. during the adding of the mixture. The mixture was then permitted to stand whereupon two layers formed, an upper layer consisting of unreacted hydrocarbons which were removed by decantation and a lower layer consisting of a mixture of glycols dissolved in the dilute acid. Sufficient sulfuric acid was then added to bring the acid strength up to 5% and the mixture was then slowly steam distilled, maintaining the acid concentration below 40% until all the glycols had been converted to ketones and driven off. 133 parts of a mixture of ketones was obtained.

The preceding disclosure and examples are given for the purpose of illustration only and are not to be considered as in any way limiting the invention.

I claim:

1. The process of converting olefins of more than four carbon atoms to the molecule to ketones which comprises treating the olefins with cold dilute aqueous hypochlorous acid, converting the resulting chlorohydrins to epoxides by means of concentrated alkaline reacting material, treating the epoxides with a dilute aqueous mineral acid to hydrolyze the epoxides to glycols, heating the glycol with a mineral acid of from 5 to 40% concentration selected from the group consisting of phosphoric and sulfuric acid and distilling off the ketone.

2. The process of treating a mixture of saturated and unsaturated hydrocarbons of more than four carbon atoms to the molecule which comprises treating the hydrocarbon mixture with cold dilute aqueous hypochlorous acid, converting the resulting chlorohydrins to epoxides by means of concentrated alkaline reacting material, treating the mixture of epoxides and saturated hydrocarbons with dilute aqueous mineral acid, separating the resulting aqueous glycol solution from saturated hydrocarbons and heating the glycol with a mineral acid of from 5 to 40% concentration selected from the group consisting of phosphoric and sulfuric acid and distilling off the ketone.

3. The process of converting olefins of more than four carbon atoms to the molecule to ketones which comprises treating the olefins with cold dilute aqueous hypochlorite in the presence of carbon dioxide, converting the resulting chlorohydrins to epoxides by means of strong caustic, treating the epoxides with a mineral acid of.from 0.1 to 1% concentration to hydrolyze the epoxides to glycol, heating the glycol with an acid of from 5 to 40% concentration selected from the group consisting of phosphoric and suluric acid and distilling off the ketone.

4. The process of converting olefins of more than four carbon atoms to the molecule to ketones which comprises treating the olefins with cold dilute aqueous hypochlorite in the presence of carbon dioxide, converting the resulting chlor hyd s to epoxides by means of solid caustic, treating the epoxides with a mineral acid of from 0.1 to 1% concentration to hydrolyze the epoxides to glycol, heating the glycol with sui furic acid of from 5 to -l0% concentration and distilling off the ketone.

5. The process of converting olefins of more than tourcarbon atoms to the molecule to ketones which comprises treating the olefins with cold dilute aqueous hypochlorlte in the presence of carbon dioxide, converting the resulting chlorohydrins to epoxides by means of solid caustic soda, treating the epoxides with a mineral acid of from 0.1 to 1% concentration to hydrolyze the epoxides to glycol, heating the glycol with sulfuric acid of from 5 to 40% concentration and distilling oil the ketone.

6. The process or converting olefins of more than four carbon atoms to the molecule to ketones which comprises treating the olefins with cold dilute aqueous calcium hypochlorite solution in the presence of carbon dioxide, converting the resulting chlorohydrins to epoxides by means of solid caustic soda, treating the epoxides with sulfuric acid of from 0.1 to 1% concentration to hydrolyze the epoxides, to glycol, heating the glycol with sulfuric acid of from 5 to 40% concentration and distilling oil the ketone.

7. The process of converting olefins of more than four carbon atoms to the molecule to ketones which comprises treating the olefins with cold dilute aqueous calcium hypochlorlte solution in the presence of carbon dioxide, converting the resulting chlorohydrlns to epoxides by means or solid caustic soda, treating the epoxides with sulfuric acid of 0.5% concentration to hydrolyze the epoxides to glycol, heating the glycol with sulfuric acid of from 5 to 40% concentration and distilling oil the ketone.

8. The process of converting trimethyl ethylcue to ketone which comprises treating the trimethyl ethylene with cold dilute aqueous calcium hypochlorite solution in the presence of soda, treating the epoxide with a carbon dioxide, converting the resulting chlorohydrins to epoxide by means of solid, caustic mineral acid oi from 0.1 to 1% concentration to hydrolyze the epoxide to glycol, heating the glycol with an acid of from 5 to 15% concentration selected from the group consisting of phosphoric and suliuric acid and distilling off the ketone.

9. The process of converting normal pentene to ketone which comprises treating the normal pentene with cold dilute aqueous calcium hypochlorite solution in the presence of carbon dioxide, converting the resulting chlorohydrins to epoxide by means of ing the epoxide with a mineral acid of from 0.1 to 1% concentration to hydrolyze the epoxide to glycol, heating the glycol with an acid of from 20 to concentration selected from the group consisting of phosphoric and sulfuric acid and distilling of! the ketone.

10. The process of converting oleflns of more than four carbon atoms to the molecule to ketones which comprises treating the oleflns with cold dilute aqueous hypochlorite in the presence of carbon dioxide, converting the resulting chlorohydrins to epoxides by means oi strong caustic, treating the epoxides with a mineral acid of from 0.1 to 1% concentration to hydrolyze the epoxides to glycol, heating the glycol with an acid of from 5 to 15% concentration selected from the group consisting of phosphoric and sulfuric acid, distilling oif ketone, then heating the remaining lycol with an acid of from 20 to 40% concentration selected from the group consisting of phosphoric and sulfuric acid and distilling on the ketone.

BENJAMIN T. BROOKS.

solid caustic soda, treat-v 

